Apart from DOO areas, in this current situation, everything is a greyer area than 50 shades despite what is written in the holy RSTL guide. I'd rather *not* have staff, especially operational staff, standing in a sneezing queue of passengers to buy a ticket. Instead (at a distance, preferably of some kilometres) they should approach the conductor, probably at the rear and ask for permission to board satisfying 'with every intention of paying for a priv'.
Packing operational staff into a queue full of sneezing coughing punters only serves to worsen shortages of staff at present. Of note, Priv is for leisure use, and there should be very little at present, given that journeys should really be undertaken only if absolutely necessary.